Major Functional Roles of Proteins in Cells
What is a catalyst?
Why do cells need catalysts?
Figure 3-13 Essential Cell Biology (© Garland Science 2010)
A model of enzyme action: A + BC → AB + C
What Limits the Rate of Catalysis?
Why isn’t the graph a linear relationship?
What is an active site?
What is the transition state?
Lock & Key
Induced Fit
Active Sites May Include Distant Residues
the enzyme lysozyme (a type of hydrolase) with several components of the active site shown in color
CPK enzyme – UNBOUND
Components of active site are shown in different colors (3 amino acid residues are labeled). A bound Zn2+ ion is in pink
With substrate BOUND (shown in teal color)
Carboxypeptidase enzyme
http://www.chemistry.wustl.edu
Figure 3-15 Essential Cell Biology (© Garland Science 2010)
Enzymes are not consumed or degraded in a chemical reaction
Figure 3-1 Essential Cell Biology (© Garland Science 2010)
Cellular enzymes function within metabolic pathways
Figure 3-1 Essential Cell Biology (© Garland Science 2010)
Cellular enzymes function within metabolic pathways
Some enzymes in the pathway are regulated and all enzyme activity has an optimal temperature, optimal pH, and sometimes other regulators